(Note: LANDRACING.COM donations are not tax deductible)


This is a public forum. The opinions expressed here don't
necessarily reflect the feelings of The Folks That Run The Site (that's us)
unless we explicitly say so, ok?


Author Topic: Team Go Dog, Go! Modified Partial Streamliners  (Read 1017889 times)

0 Members and 3 Guests are viewing this topic.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1230 on: June 14, 2013, 12:24:30 AM »
Calc sheet 1

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1231 on: June 14, 2013, 12:25:29 AM »
Calc sheet 2

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1232 on: June 14, 2013, 12:40:20 AM »
The first task is to measure the volume between the cylinder wall and the top ring land, above the upper surface of the top ring, and below the piston deck.  The cylinder diameters were measured by the machinist using his micrometer.  A smart guy would measure the ring land diameter and depth before he installed the piston.  I am measuring it afterward using the shanks of these numbered drills as "Go" "No Go" gages.  These are number 60 to 80 drills.  Hobby shops have them.  Measurements are taken at the front , back, and on each side.  These are averaged to get the clearances.  The pistons rock a little bit in the bores and this makes the clearances different on the backs and fronts.

The volume is 0.00893 cubic inch or 0.146 cubic centimeter.  That is pretty small and hardly significant for this engine.  This is not always the case.  Sometimes this volume can be large enough to make a difference in the calculated compression ratio. 

   

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1233 on: June 15, 2013, 10:42:06 AM »
The swept volume is measured.  This is the distance the piston travels x the bore area.  It is the engine displacement for classification, marketing, and insurance purposes.  In the past I ran 790cc and 865cc engines in the 1000cc class.  Now the motor is just a few cc shy of the 1000cc limit.  It is a good idea to verify it is legal.  Also. I need to check the stroke and deck clearances.  My experience with older British stuff tells me there can be problems here.

The piston is moved to top dead center (TDC) using a dial gage.  I check to verify the measured TDC coincides with the TDC mark on the flywheel.  I do this for both cylinders.  This is a very important thing to check on multi cylinder engines with pressed together crank shafts.  Sometimes one piston can be out of time a degree or two.  The mark might be in the wrong place, too, and this can happen on any engine.  This motor is OK.

All sorts of shim stock is dug up and I cut off little strips for feeler gages.  A valve shim for the standard engine pressed down on the cylinder deck and I measure the clearances between the two decks at four places 90 degrees apart.  The pistons rock in the bores and there are manufacturing tolerances on the piston tops.  The readings are a little bit different and I expect this.  The readings are averaged to get the deck clearances for each cyl.  The calcs say the pistons go up to within 0.010 of the top of the cylinder on each pot.

The pistons are moved to bottom dead center (BDC).  The distances between the cylinder and piston decks are measured again and they are averaged for both cylinders.  The piston stroke for swept volume calculation is the distance between the two decks at BDC minus the distance between the two decks at TDC.  It is 2.687 - 0.010 = 2.677 inches.  The engine displacement figgers out to be 995cc.

Sometimes a cylinder on a multi will "run hot."  It is important to check to make sure it is properly timed and it does not reach TDC before the others.  Also, it is critical that it has the correct compression and it does not have less deck clearance than its companions at TDC. 

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1234 on: June 15, 2013, 10:43:51 AM »
Two more pix to go with the last post.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1235 on: June 15, 2013, 11:13:50 AM »
A slightly raised part of the piston deck is visible between the valve pockets in "2013 Build Diary 287."  This deck is a couple of thousands of an inch above the cyl deck.  The cylinder head is flat in this area just behind and ahead of the valves as shown in the attached picture.  The distance between the two is the smallest piston-to-head clearance.  Arias recommends a minimum of 0.040 for engines with steel connecting rods like this one.  This motor is at that clearance with the 0.043 inch thick copper head gasket I am using.  Triumph performance makes a 0.040 thick head gasket.  I cannot use it on this motor to gain compression.  I will have too little piston-to-head clearance if I do.

This motor will loosen up with use.  The pistons are very wide in comparison to their height.  The edges of the piston decks might hit the bottom of the cylinders, at the fronts and backs of the pistons, if the piston wears enough to rock.  I need to take the head off to check for this every couple of years.

   

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1236 on: June 16, 2013, 12:33:04 AM »
This morning I got up and out early and finished late.  The bike runs.  It has a fuel leak like a stuck float and the front brake needs to be bled.  Sometime tomorrow it should be out on the road.  The highway cops are setting up saturation patrols on the stretch of highway that has Test Hill.  I need to find another road with a steep incline to seat the rings.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1237 on: June 16, 2013, 10:59:08 AM »
Now it is time to measure the combustion chamber volume below the cylinder deck when the piston is at TDC.  This is a positive volume if the piston deck is below the cylinder deck and the crown is flat.  It is a negative volume is the piston deck is above the cylinder deck, or if the piston deck is below the cyl deck and the piston has a lot of crown.

First, I put a rag on the back of the engine over the transmission.  Then I put a big chunk of train track on the top of the rag.  The magnetic dial indicator base adheres to the track.  The indicator is set up to measure piston travel.  The piston is moved down exactly 0.300 inches.  This distance needs to be enough so the piston crown does not stick out above the cylinder deck.

The top ring land is sealed with moly grease as shown.  This volume is measured in a previous step.  Also, the grease keeps measuring fluid from leaking past the rings.

A plexiglas plate is made to fit over the bore.  Typically some pressure is applied to the plate to hold it down.  This will distort a thin plate.  I make the plate out of thick plastic so this will not happen.  A 1/8 inch hole is drilled in the middle to let the fluid in.  A 1/16 hole is drilled near the edge to let the air out.  Some moly grease is smeared on the cylinder deck to make a seal and the plate is placed on top of the bore.  The air hole is located at the high point along the cyl edge.

Water is hard to use for this measuring.  It has a lot of surface tension and resulting meniscus.  It is hard to read the fliud level with the graduations on the burette.  Some folks use mineral oil for the burette work.  Others use colored alcohol.  I am using Ford automatic tranny fluid 'cause I have a bottle of it and no Ford to use it in.  All of these fluids have minimal menisci and it is easy to read the burette graduations.

The portion of the burette below the valve is filled with fluid before measuring starts.  The burette is graduated and intended to be used in this condition.   

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1238 on: June 16, 2013, 11:23:39 AM »
The burette is from comp Cams and it is 100cc capacity and about 2 feet tall.  The graduations are at 0.2 milliliter (ml) intervals.  This is a bit coarse for little motorcycle combustion chambers.  A smart guy would use a 50cc burette about 2 feet tall with 0.1 ml grads.  He would place some objects of known volume, like valve shims, in whatever he was measuring if it was more than 50cc.  The volume of the shims would be added to the volume from the burette to get the total volume.  This is what I did years ago and I remembered it after I ordered the burette I have.  A 100cc burette is the right size for car motors.  The picture shows the burette graduations.  The cylinder is filled with fluid until it almost pees out of the vent hole.  This is done for both pots.

The cylinder swept volume is calculated for 0.300 inches of travel.  The swept volume is subtracted from the measured volume.  The combustion chamber volume below the cylinder deck is positive if this is a positive number.  The volume below the deck is negative if it is negative.  Old style hemi engines are almost always negative.  This Triumph is positive.  The slight crown on the piston does not fully compensate for the depressions in the valve pockets.  The volumes below the cyl deck average out to 0.093 cubic inch or 1.52 cubic centimeter.  The measurements were slightly different on the cyls and this is within the precision range at which I can read the levels.  A burette with 0.1 ml graduations would be used to determine if these volumes are different.  The burette I am using and my old eyeballs are not precise enough to determine this.             

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1239 on: June 17, 2013, 12:10:09 AM »
The doctor wants me to live for a long time.  Eating red meat and excessive drinking are verboten.  Heck, its Father's Day.  Rosie was taking me down to one of the locals for a monster steak dinner and as many pints as I could drink.  That steak and beer tastes better when a fellow does not have it very often.  We drove by a little street and Rose said "The guy I sold your truck to lives here.  I remember it from the paperwork."  The first four wheeled vehicle I owned was a 1974 Toyota HiLux truck.  My Pa sold it to me for $1,000 when I was in college.  It is a good truck and I kept it until 2008.  I would have it now except parts are hard to get.  A guy fresh out of jail bought it.  He had tattoos hiding the needle track on his arms.  He said he wanted to start a new life and he needed a nice truck and this Toyota was the one.  Rose was selling it and he bought it for $1800.

Occasionally I see the truck running around with the new owner.  We drove down the little street and there it was.  Polished up and gleaming red.  A new set of mag wheels, and otherwise it was original.  There were several cars in the driveway.  The way this one was parked showed it had pride of place.  It was his favorite.  A 39-year old truck with a charmed life.  Always loved.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1240 on: June 17, 2013, 10:51:32 PM »
Now it is time to cc the combustion chambers.  Each one is greased and wiped of until there is only a thin ring of grease around the valve edges to seal them.  Basically, wipe out all of the grease you can.  Enough will be left behind to seal the valves.  Each chamber is filled just like it was done with the cylinders.  The volumes are averaged and it is 2.581 cubic inch per chamber or 42.3 cubic centimeters.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1241 on: June 18, 2013, 12:18:34 AM »
The head gasket hole volumes are measured.  The holes are not assumed to be round or to be the same size.  Each hole is measured front to back and side to side.  The 0.062 inch thick gasket measures out to 0.717 cubic inch per hole, average, and the 0.043 inch thick gasket has a 0.498 cubic inch hole.  I also lay the gasket out on the head and make sure it does not project into the combustion chambers.

These are the last measurements.  Tomorrow everything will be summed up and I will figure out my compression ratios.


Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1242 on: June 19, 2013, 12:24:05 AM »
The total volume is the combustion chamber volume + the swept volume.  The compression ratio is the total volume / the combustion chamber volume.  The compression ratios are 10.5 to 1 with the thinner 0.043 head gasket and 9.9 to 1 with the 0.063 gasket.  The pistons I ordered are specified as 11.5 to 1.  That is probably right for a standard original equipment cylinder head.  Note the flat valve faces and the thick valve margins on the stock head.  The valve heads sit on top of their seats.  The racing head has dished valve faces, relieving around the larger intake valves, and the valves sit farther down in their seats.  This increases the combustion chamber volume and it lowers the compression ratio.

Originally I was going to use the thinner head gasket on the salt and the thicker one for the street.  A 10.5 to 1 ratio can be used on the street so I will use the thinner gasket for road and racing.  I will use the thicker gasket if I run the standard cylinder head.

The compression ratio measuring is done.  It helps me a lot  There is no substitute for working with real numbers and I have them now. 

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1243 on: June 19, 2013, 12:45:12 AM »
I forgot the picture of the standard cyl head.  Here it is.

An electroechocardiogram is needed once in a lifetime for FIM.  I had one a few years back and passed.  The stress test needs to be done every three years and this was the year to redo it.  The nurse took my baseline electrocardiogram last week and she told me to show up this afternoon for the test.  She said "Don't eat a big lunch.  We don't want you puking on our machine."  Lovely advice.  I had strawberry pie for lunch.  At least it would taste good coming back out.

The nurses wired me up.  I said "I am a pre-old guy.  Sort of delicate.  Stop the machine when I have passed the test.  Do not try to kill me like you did last time."  The nurse said "You stop the test, not us.  Tell us when you cannot handle any more."  Wonderful.  Last time that meant I wanted to barf, saw black spots in front of my eyes, and had horrible leg cramps.

The machine started.  The belt was level and it moved slow.  Gradually they increased the speed and the tilt.  I walked faster and faster.  The table was tilted steep and the speed was turned up more.  I needed to run.  I did this for a half second and said "enough."  They stopped the awful device.

The nurse said "Had enough?"  I said, "I'm not really tired.  It is undignified for a gent my age to engage in running."  She looked at the graphs, etc and said, "Well, you passed.  Another 20 seconds and we would have rated you excellent."  That would have been a long 20 seconds, for sure.

Offline wobblywalrus

  • Hero Member
  • *****
  • Posts: 5308
  • Age: 67
  • Location: backwoods Oregon
Re: Team Go Dog, Go! Modified Partial Streamliners
« Reply #1244 on: June 19, 2013, 11:23:13 PM »
Triumph recommends priming the oil pumps prior to engine assembly.  It is about four months between assembling the lower end and starting the engine.  I am afraid the pumps have lost their primes.  The joint where the cylinder head feed line joins the crankcase is a place to pour in some oil for priming one of the pumps.  The other pump is primed through an oil passage plug on the cylinder.  It is a good idea to fill the pumps and oil passages on motors before they are started the first time.  Yamalube All Purpose 10W-40 mineral based oil is used to break in this engine.  It meets JASO T903:2006 specs and it should give good lubrication and also allow the piston rings to seat.